- Tye Sheridan as Scott Summers / Cyclops: A mutant who can project energy beams from his eyes and wears a visor or sunglasses to control them and the younger brother of Havok.
- Sophie Turner as Jean Grey: A mutant who is scared of her telepathic and telekinetic power and one of Charles Xavier's most prized students.
- Olivia Munn as Elizabeth Braddock / Psylocke: A mutant who becomes one of Apocalypse's horsemen.
- Lucas Till as Alex Summers / Havok: A mutant who has the ability to absorb energy and release it with destructive force and the older brother of Cyclops.
- Alexandra Shipp as Ororo Munroe / Storm: A mutant who can control weather and becomes one of Apocalypse's horsemen.
- Evan Peters as Peter Maximoff / Quicksilver: A mutant who can move at superhuman speeds and the son of Magneto.
- Kodi Smit-McPhee as Kurt Wagner / Nightcrawler: A German teleporting mutant and one of Charles Xavier's new students.
- Ben Hardy as Warren Worthington III / Angel / Archangel: A winged mutant who becomes one of Apocalypse's horsemen.
- Lana Condor as Jubilation Lee / Jubilee: A fashionable student at Charles' school who can generate pyrotechnic energy plasmoids from her hands.